This invention relates to a method for producing D-.alpha.-amino acids, particularly by an enzymatic process.
D-.alpha.-amino acids as a class constitute many compounds and have potential utility as agricultural chemicals or medicinal agents or they can be used as starting materials for these chemicals or medicinal agents. For example D-p-hydroxy phenylglycine can be used as a starting material for the antibiotic, amoxycillin.
It is known that D-.alpha.-amino acids can be prepared by chemically hydrolyzing 5-substituted hydantoins to DL-.alpha.-amino acids, and then separating the D-.alpha.-amino acids from the racemic hydrolysis reaction product. This method, however, is rather complex in that it requires the separation of D-isomers and racemization of the L-isomer of the amino acids.
It is also known that 5-substituted hydantoins can be enzymatically converted to L-.alpha.-amino acids (Japanese Published Examined Patent Application No. 13850/1967). It is further known that the 5-substituted hydantoins can be enzymatically converted to N-carbamyl-D-.alpha.-amino acids (Japanese Published Unexamined Patent Application No. 10484/1977, and Proceedings of 1977 Annual Meeting of the Agricultural Chemical Society of Japan p 215 (1977)). In the latter method, however, additional process steps are required to convert the N-carbamyl-D-.alpha.-amino acids to D-.alpha.-amino acids.
Therefore, a need has continued to exist for a simpler and more economic method of obtaining D-.alpha.-amino acids.